Apparatus for hot working metal



MarTi 27; 1928. 1,663,576

w. VON KbssowsKl APIARATUS FOR HOT WORKING METAL Filed Nov. 8. 1924 Patented Mar. 27, 1928.

. UNITED STATES' PATENT OFFICE.

APPARATUS FOR HOT WORKING METAL.

Application filed November 8, 1924, Serial No. 748,794, and in Poland July 12, 1924.

My invention relates to the hot-working of metal and more especially to an im rovement in the manufacture of corrugate tubes by heating a smooth sheet metal tube by zones and exerting axial pressure on the tube, as described in the specification of Letters Patent of the United States granted to Wladyslaw Maciejewski No. 1,010,931, according to which the corrugation last made is protected from the action of the heat on the blank forlmaking the next corrugation by applying a cooling medium, such as water, a heat insulating rmg or both.

This method involves several drawbacks. Quenching with water causes the metal to be hardened in the zone where a fresh corrugation shell be formed and considerably delays the heating of the fresh zone. This drawback can be obviated by using an insulating ring, but the ring must be displaced along the tube Whenever a fresh corrugation shall be produced. This is connected with serious practical diflicultics due to the flame which burns near to the ring and further'due to the rotation of the tube.

To this end I provide means for protecting the corrugation last formed against the action of the flames heating a fresh zone, by means of a veil of air which forms a protective screen between the last corrugation and the heating zone.

In the drawings ailixed to this specification and forming part thereof a device cmbodying my invention is illustrated diagrammatically by way of example.

In the drawings Fig. 1 is a cross section and Fig. 2 a longitudinal section.

The tube 1, to which rotation may be imparted by any suitable means (not shown) is surrounded by an annular casing 3 arranged to allow the radial passage of the flames emerging from the burners 2. An annular air supply chamber 4' adjoining and forming part of the casing 3 is supplied with cooling air by pipes 6, preferably under the same ressure and from the same source as the air of combustion su plied to the burners 2. The air esca es rom the chamber 4: in radial direction 1; rough a slot 5 and forms a veil or screen of an inch in thickness and surrounding the tube.

The casin 3 with the burners 2 is mounted on a frame which is adapted to be moved along the tube 1.

The corrugation last made is indicated at b. The next corrugation is to be formed by axial compression of the tube after heating the zone a. The corrugation Z) is protected from the action of the flames in the zpne a by the veil of air emerging from the s 0t 5.

Obviousl it is inevitable that the air is heated whi e flowing through the chamber 4 and escapes at the slot 5 at a comparatively high temperature, but the temperature is not raised to such an extent as to transmit heat to the corrugation b. Experience shows that it is possible to heat the zone a to the temperature required for forming the corrugation while the adjacent finished corrugation 5 remains quite black.

The rate of operating is greatly accelerated and the consumption of gas is reduced by about per cent.

The veil of air and the flame being interdependent, if the air supply fails, the burners cease to operate also.

The present invention refers to the preparation of the blank and can be utilized in connection with other operations, such as riveting or the like as well as in corrugating.

I wish it to be understood that I do not desire to be limited to the exact details of rection and means connected with said cas- WAGLAW v. Kossowsm. 

